The invention relates to an environmentally friendly and cost effective system and process for treating natural gas.
For natural gas sweetening applications where hydrocarbon recovery is of prime importance to the customer, the current solutions of a two stage membrane system or a stand-alone amine guard formulated solvent (AGFS) system do not offer a cost effective, environment friendly and high hydrocarbon recovery solution. There exist numerous natural gas sweetening opportunities in the world (especially in the Southeast Asia region), where there is a need to provide a technological solution that would meet all customer expectations including high hydrocarbon recovery, environmentally friendly, and cost effectiveness.
A two-stage membrane system offers reasonably high hydrocarbon recovery as compared to a single stage system, but the hydrocarbon content of the permeate stream from the two-stage system makes it unacceptable for venting. Similarly, a stand-alone AGFS unit can offer the best in class hydrocarbon recovery with an acid gas stream with extremely low hydrocarbon content, but it may not be a cost effective solution to a customer's requirements.
The flow scheme of the present invention offers nearly 100% hydrocarbon recovery, and it is environmentally friendly and cost effective.